Archive for the ‘C4 Corvette vacuum power brake booster’ Category

Mounting the C4 Corvette Vacuum Assisted Power Brake Booster in the Hot Rod

Well, the festive season of Christmas and the New Year with lots of visiting, good food, and entertaining has come to an end. We only had one major snowfall in our area. For the last few days the weather has been sunny and usually warm. It will be a good feeling getting back into the shop and continue working on the 1929 Ford roadster hot rod. With the shop warm and some great classic rock tunes the environment will be perfect for working on the hot rod.

The time has come to install the C4 Corvette vacuum assisted power brake booster in the 1929 Ford roadster hot rod. When I originally designed the chassis / frame for the hot rod, I decided it would be a great idea if I could incorporate as many of the C4 Corvette parts removed from the 1986 Corvette Indy Pace car convertible as possible into the custom build of the custom Model A Ford roadster. Basically my intention was to have a C4 Corvette disguised or cloaked as a Model A Ford. So, it made sense to use the entire braking system including the vacuum assisted power brake booster with the master cylinder. I did decide early on in the chassis / frame design to mount the brake booster and master cylinder on the chassis just underneath the driver’s seat. The power booster is a bit larger in diameter then most aftermarket booster available for custom hot rods. This is not much of a problem, as the 1929 Ford roadster hot rod using the C4 Corvette suspension will have the chassis / frame sitting a safe distance from the road surface. Basically the 1929 Ford roadster hot rod will be a high boy design using modern suspension.

The power brake booster and master brake cylinder are a fair distance to the brake pedal assembly. After a considerable amount of thought, I decided to use a 0.75 inch (3/4”) round steel shaft to make this connection. A heim joint was used to connect to the brake pedal assembly. This part was easy. All I needed to do was drill a hole on the metal lathe in the end of the shaft so that I could tap the hole using a 0.375 inch ( 3/8”) NFT tap. The outer diameter of the heim joint was almost the same diameter of the 0.75 inch (3/4”) extension shaft making this end very neat and tidy.

Not wanting to modify the shaft coming out of the C4 Corvette vacuum power brake booster, I had to come up with an idea of connecting it easily to the extension shaft. After sleeping on it for a few nights, and just looking around the shop a bit, I realized that some 0.75 inch (3/4”) square tubing could be used as a coupling adapter. A small amount of material was removed from the round extension shaft using the metal lathe so the shaft would fit into the square tubing coupler. Using the MIG welder the square tubing was welded to the round shaft and trimmed up on the metal lathe. To connect the vacuum power brake booster to the coupling and extension shaft a two small shims were use on either side of the brake booster shaft and fitted tightly inside the square tubing. The extension shaft with the newly made adapter was bolted to the brake booster shaft. The newly modified power brake booster with the master brake cylinder was bolted to the chassis and the brake pedal. Of course I needed to get in the hot rod and try the brakes out. As expected everything worked smoothly.